1. Technical Field
The technical field relates to a printed circuit board on which electronic components can be mounted on both sides. Moreover, the technical field relates to a method for mounting electronic components on a both-side mounting printed circuit board.
2. Related Art
Conventionally, there has been a method for mounting electronic components using a both-side mounting printed circuit board that includes a primary mounting surface in the one surface and a secondary mounting surface on the other surface, to which a plurality of identical individual boards are allocated. In such a printed circuit board, for example, after the electronic components are mounted on the primary mounting surface, the printed circuit board is turned over to mount electronic components on the secondary mounting surface.
As a method for increasing efficiency in mounting the electronic components on the both-side mounting printed circuit board, for example, a method described in JPA-9-223856 is cited. In the mounting method described in JPA-9-223856, a plurality of individual boards are adjacently arranged on the printed circuit board, and at this time, a front surface of one individual board and a back surface of another individual board are arranged on one mounting surface of the printed circuit board, and a back surface of the one individual board and a front surface of the other individual board are arranged on the other mounting surface of the printed circuit board. That is, the front surface and the back surface of the individual boards are arrayed so as to be located alternately. Electronic components are mounted on the one mounting surface of the above-described printed circuit board, and then, the printed circuit board is turned over with a border line between the one individual board and the other individual board used as an axis for turning over to mount electronic components on the other mounting surface of the printed circuit board. Thereby, mounting positions of the electronic components are identical when the printed circuit board is turned over, which allows the same mounting jig to be used on the primary mounting surface side and a secondary mounting surface side, and increases efficiency in the electronic component mounting.
When electronic components are mounted on a printed circuit board, generally, reflow soldering is performed. The reflow soldering raises a temperature of the printed circuit board. At this time, generated heat causes warpage in the printed circuit board. This warpage changes mounting positions of the electronic components (i.e., spacing of portions where each of the electronic components is soldered) on the printed circuit board. As a result, the spacing between the electronic component soldering portions and the spacing between terminals of the electronic component are misaligned, which may lead to a soldering failure. In recent years, down-sizing of the electronic components has been developed, and miniaturization of a pitch between the terminals has been advanced. The electronic component with a narrow pitch between the terminals is especially susceptible to the warpage, and thus, the above-described problem is easily caused.
In order to solve the above-described problem, an object is to provide a printed circuit board capable of increasing mounting efficiency while reducing mounting failures of electronic components.
Moreover, in order to solve the above-described problem, another object is to provide a method for mounting electronic components capable of increasing mounting efficiency while reducing mounting failures of the electronic components on the printed circuit board.